Luminous indicator



Nov. 20 1923. 1,474,816

E. W. DAY

LUMINOUS INDICATOR Filed Aug. 23. 1917 2 Sheets-Sheet 1 l/V VEN TOI? IMM;

Nov. 2O 1923. 1,474,816

E. W. DAY

LUMINOUS INDICATOR Filed Ausl. 23. 191'? 2 Sheets-Sheet 2 /N VEN TOR V 70W/gy WAY. I

Patented Nov. 20,1923. i

UNITED STATES 1,474,816 -PATENT OFFICE.

EDWIN'W. DAY, or BaooxLYN, NF'W Yom;

LUMINOUS `INDICATOR.

To all whom/i315 may concern Be it known that I, EDWIN IV. DAY, a citizen of the United States of America, residing at 273 89th St., Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements Vin Luminous Indicators, of which the fdllowing is a specification.

This invention relates to visual indicating devices or in other Wordsto indicators of the kind which must be seen to be read.

The main obj ect of the invention isto construct such indicators so that they may be read with 'facility not only in the day light or When illuminated by artificial means but also in the dark. For this purpose I prefer' to makeuse of a radio-active substance or substances so situated as to illuminate that part of the indicator which it is most essential to see. l

My invention is especially adapted for Compasses such as used by aviators and soldiers. I am aware that it has been proposed to use radium paint in marking compass dials, whereby the dials themselves are rendered self-luminous, but it has been found objectionableifor several reasons. A comparatively large amount of radium is required to paint all of the compass markings and the lubber line so that the cost of constructing compassesin this manner is necessarily high. Furthermore, the liquid, such as alcohol, with which it is found ydesirable to fill Compasses, very often seriously daniages the radium paint ,and causes rapid den terioration thereof. In my invention this objection to the use of radium is over-come and the cost of the compass greatly reduced. Also a much-better, and therefore a more costly grade of material is necessary Where the'material is used in a liquid than Where it is dry so that here too, the cost ofthe instrument is reduced by using my method of illumination.

When the luminous material is applied dil rectly to the markings or hands of instruments in the' forni of a paint or paste, the small particlesof radio-sensitive substance upon which the radium rays must-act to produce light become affected by the air, and gradually lose their value. One of the advantages-of placing the material in an air tight tube is therefore obvious. Referring tothe drawings:

Fig. 2 is a plany View thereof.

Fig/3 is a bottom plan View of the radium lamp and casing. Fig. 4 is a detail of a, Washer used to keep Water out of the lamp.v

showing the application of my invention thereto.

Fig. 6 is a ysideelevation thereof partly in section.

Fig. 7 shows the application of the inventionto a Watch. y

Fig. 8 is a detail of/Fig. 7.

Fig. 9 'shows a modified method. of applying the invention to a watch.

The compass casing is indicated at 1. From the bottom thereof rises the postl 2 on thetop 2 of which a pin 3 rests. The said pin serves to rotatably support the magnetic element or elements 4 to which is secured the compass rose or a card 5. The reference index 9 is shown as supported on a Wire 20.

The casing is shown as provided with a glass top 6 and is' designed to be completely filled. with a limpid, clear liquid`7 such as alcohol.

According to my invention Ifconcentrate the-radio active substances which have here- .6.0 Fig. 5 -is a front elevation of a speedometer tofore been spread over the entire compass card in a small tube or container 8 which` is secured nea-r the reference index or lubber l, line 9 so as to illuminate theV same and the adjacent portions of the vcard 5. The said radio active substance is preferably placed within the tubein a dry or powdered'form and consists preferably of a mixture of a radio-active salt and a finely divided fiuorescent substance such as zinc sulphide. By

using these substances in a dry or powderk form a greater light emissivity is obtained than When applied in the form o f a paste or paint on the compass markings, since certain rays probably principally the a rays arey round bore with the same cubical'contents since a greater surface of radio-active inaterial is presented. The said member 10 isv shown as detachably fastened to the com- Fig. l is -a vertical section of a compass. casing by set screws 1 2 ad'aoent or.

" above the lubber line 9. At the point Where 6 5 lof the. -radium l V.be

the container 8\isj securecLthereto, member 10 is preferably made concave on its under surface as shown at 13, so as to act in effect as 'a reflector for the radium rays.r

U'EPreferably the f under surface of said The container or tube 8 is preferably'made' .of glass and sealed at both ends so that the radium is protected from the action of moisture or forelgn substances. The under surface 13 of membei` 10 may also-be protected from moisture by a rubber gasket 15 (see Fig. 4). While in Figs'. 1 and 2 the container and reflector are shown as placed directly over the card and lubber line-in (or- 'der to obtain maximum illumination, they i A' do not interfere with the observer in this".

position. as is shown by the position of the observerseye 16in Fig. 1.

- tion applied to an automobile speedometer 22, in which instance the tube 8 containing v.the radio-active substance maybe attached to the inside of the v speedometer case 23 d irectly over the Window 24 through which the observer reads the markings 25, and back of the lubber line 26. l

Figs. 7 and 8 show tlie application of the invention topa Watch 27 Av glass bulb 8 containing the radio-active substance is ,shown within a metal casing 28 inserted in a h'ole in the center of crystal 29.

The radiationv from this point will illuminato the entire dial and also show the position of the hands.

In Fig. 9, I' show a tube 8b of radio-active substance belovi1 the hands 30 of the Watch. The tube may rest on the dial 29 and surround stem 31. A shield 32 over'the tube 8b ma-ywhile serving to hold said tube in l place,` also prevent the direct emanation` from reaching theeye of the iobserver, so

light reflected from the dial. f s

In accordance wi'ththe provisions of the Y patent statutes, I have herein described the principle of operation of my invention, t0-

gether with the apparatus, which I now con.- sider to represent the best embodiment thereof, but I vdesire to have it understood that the apparatus shown is only illustrative andA that the invention can be carried out by other means. Also, while it is designed to use the variousr features and elements in the combination and relations described, some of these may beralte'red and others'omitted results outlined, fand thlinvention `extends in .th

ldicating -vvithout'interfering with the more general] scope of my invention. Also the application of my invention to other types of indica- ,tors'ivill be obvious from the foregoingde-I 2. In a visual indicator, the combination With` a `rotatable indicating element and a stationary indicating element adapted for conjoint reading, a radio-active substance supported to vone side of; said elements, and

fluorescent means on the side of said radium opposite from 4said elements for increasing the illumination of said elements.

In Figs). 5 and I have shown my invend. In a visual indicator, the combination.

with a rotatablindicating element and a y,stationary indicating element adapted for conj oint, reading, a radio-active substance and a contalner therefor, and a concave fluorescent holder forsaid container rpositioned'v adjacent 'said elements.

4. In a compass, the combination with a basing, of a compass rose pivotally supportv edl therein, a reference index therefor, a holder supported to .one side of said index,

and having a fluorescent inner surface, and

ing a flattened bore and luminous'material that vthe eye may be more sensitiveI to the )in saidb'ore, and means :for supporting vsffld ment adapted to.coop.erate tlerewit a j transparent co tainer having a ilattened' u.

bore and mun adjacent said elements, luminous material 4`sealed in said bore, and

from direct view. l l 8. In a visual indicator, a stationary inement and a rotatable indicating element ad pted for conjoint' reading, a.

`means for shielding said luminous material `transparent containeruhaving a flattened bore and a radio-active substance sealed in said bore, and a. concave fluorescent' holder o for said containerl positioned adjacent said elements. l

9. In a visual indicator, a stationary indicating element and a rotatable indicating 5 element adapted for conjoint reading, a

transparent container adjacent said elements, luminous material in said container, and a concave member adJa/cent said container for shielding said material from direct View, said concave member having a flu- In testimony whereof I have affixed my signature.

EDWIN W. DAY. 

